Some light-emitting devices using, for example, an LED element as a semiconductor light-emitting element include a substrate having a front surface on which a wiring pattern is formed, plural LED elements mounted on the wiring pattern of the front surface of the substrate, and a lens that is arranged on the front surface of the substrate and controls the light emitted from the respective LED elements.
In these light-emitting devices, generally, heat generated by the LED elements is conducted to the substrate and is radiated from the back surface of the substrate to lighting equipment on which the substrate is mounted. Therefore, reduction of the light output of the LED element and reduction of the life of the LED element are suppressed.
In ceiling-mounted light-emitting devices in which heat is radiated from the back surface of the substrate, although heat is conducted from the back surface of the substrate to a top plate of an equipment body, a relatively non-conductive material such as gypsum board or wood may be used for the ceiling member to which the top plate of the equipment body is attached. Thus, a required heat radiation property may not be realized by the top plate of the equipment body. This is often addressed with a countermeasure such as to a gap between the top plate of the equipment body and the ceiling member, which increases the thickness of the lighting equipment.
In some light-emitting devices, the area of a wiring pattern formed on the front surface of a substrate is wide, heat generated by LED elements is conducted to the wiring pattern having the wide area, and the heat is radiated to the air from the wiring pattern, so that adequate heat radiation from the front surface of the substrate is realized.
In some light-emitting devices a substrate on which plural LED elements are mounted is arranged inside a housing, plural spacers are provided between the housing and the front surface of the substrate, and the substrate is fixed to the housing by screws inserted in the respective spacers. In this light-emitting device, heat generated by the LED elements is conducted to the substrate, is conducted from the substrate to the housing through the spacers and the screws, and is radiated from the housing.